Conductive fiber brush cleaner having separate detoning and scavenging zones

ABSTRACT

A conductive fur brush cleaning assembly for an image processing apparatus. The cleaning assembly has a casing, a plurality of rotating components within the casing and a plurality of sealing devices that divide the casing into a scavenging zone and a detoning zone. The sealing devices prevent airborne marking particles from traveling from the detoning zone into the scavenging zone.

CROSS REFERENCE TO RELATED APPLICATION

Reference is made to and priority claimed from U.S. ProvisionalApplication Serial No. 60/317,393, filed, Sep. 5, 2001 entitled DETONECLEANER HAVING SEPARATE ZONES USING FLAPS.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to a cleaning assembly for, anelectrostatographic marking engine, and more particularly to a cleaningassembly which is separated into different zones to prevent airbornewaste toner particles from migrating from the detone zone to thescavenging zone.

2. Description of the Related Art

In a typical commercial reproduction apparatus (electrostatographiccopier/duplicators, printers, or the like), a latent image chargepattern is formed on a uniformly charged dielectric member such as abelt or drum. Pigmented marking particles are attracted to the latentimage charge pattern to develop such images on the dielectric member.Printing material, commonly referred to as a receiver member, is thenbrought into contact with the dielectric member. An electric field, suchas provided by a corona charger or an electrically biased roller, isapplied to transfer the marking particle developed image to the receivermember from the dielectric member. After transfer, the receiver memberbearing the transferred image is separated from the dielectric memberand transported away from the dielectric member to a fuser apparatus ata downstream location. There, the image is fixed to the receiver memberby heat and/or pressure from the fuser apparatus to form a permanentreproduction thereon.

However, not all of the marking particles are transferred to thereceiver member and some remain upon the dielectric member. Therefore, acleaning assembly is commonly used to remove the excess markingparticles. The cleaning assembly usually includes an electrostaticcleaning brush, a detoning roller, a skive, and a receptacle to hold theexcess marking particles (waste marking particle). The components withinthe cleaning assembly generally rotate to remove waste particles.

However, a problem occurs when marking particles that are removed fromthe detoning roller by the skive becomes airborne and are attracted backto the cleaning brush. This reduces the efficiency of the cleaningassembly because waste marking particles may have to be removed from thecleaning brush a number of times before it reaches the waste markingparticle receptacle. More importantly, it is also possible for suchairborne waste marking particles to be carried outside the cleaningassembly through the viscous boundary layer of air created due to therotation of the cleaning brush. If these waste marking particles exit inthe cleaning assembly, it can contaminate the outside surfaces of thecleaning assembly and/or the remaining portions of the image processingapparatus. Therefore, there is a need to prevent waste marking particlesthat are removed from the detoning roller from becoming airborne andre-entering the scavenging zone of the cleaning assembly. The inventiondiscussed below addresses this problem by providing a solution that usesflaps or some similar device to divide the cleaning assembly into ascavenging zone and a detoning zone whereby, once the waste particlesenter the detoning zone, they are prevented from re-entering thescavenging zone.

SUMMARY OF THE INVENTION

In view of the foregoing and other problems, disadvantages, anddrawbacks of the conventional cleaning assembly, the present inventionhas been devised, and it is an object of the present invention, toprovide a structure and method for an improved cleaning assembly.

In order to attain the object suggested above, there is provided,according to one aspect of the invention a conductive fur brush cleaningassembly for an image processing apparatus. The cleaning assemblyincludes a casing, a plurality of rotating components within the casing,and a plurality of sealing devices that divide the casing into ascavenging zone and a detoning zone. The sealing devices preventairborne waste marking particles from traveling from the detoning zoneinto the scavenging zone. The rotating components include a detoningroller in contact with at least one of the sealing devices. The cleaningassembly sealing devices can comprise a plush fabric seal or a flap. Thesealing devices have sufficient rigidity to maintain contact with therotating components while the rotating components are rotating. Thesealing devices can be air curtains, flaps, and/or plush fabric seals.

The invention also includes a method of controlling airborne wastemarking particles in a conductive fur brush cleaning assembly for animage processing apparatus. The method comprises producing rotatingcomponents within a casing, and dividing the casing into a scavengingzone and a detoning zone using sealing devices. The sealing devicesprevent the airborne waste marking particles from traveling from thedetoning zone into the scavenging zone.

Thus, the invention physically separates the cleaning assembly into ascavenging zone and a detoning zone using, for example, flaps orplushes. Such physically separated zones reduce the volume of wastemarking particles from the scavenging zone to increase the cleaningefficiency of the operating components in the scavenging zone. Byproviding physical structures that create zones, the invention issuperior to conventional structures and contains waste marking particleswithin the detoning zone, thereby reducing waste toner contamination ofthe cleaning (detoning) components of the cleaning assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, aspects and advantages will be betterunderstood from the following detailed description of the preferredembodiments of the invention with reference to the drawings, in which:

FIGS. 1A and 1B are side elevation schematic views of a color printapparatus utilizing a cleaning assembly of the invention;

FIG. 2 is a side elevation schematic view showing in greater detail thecleaning assembly forming a part of the apparatus of FIG. 1; and

FIG. 3 is a side elevation schematic view showing in greater detail theinventive flaps within the cleaning assembly of FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1A illustrates an apparatus in which the invention may be used. Aconveyor 6 is drivable to move a receiving sheet 25 (e.g., paper,plastic) past a series of imaging stations 15. One of the imagingstations 15 is shown in greater detail in FIG. 1B.

With the invention, a primary image member (for example, aphotoconductive drum) 1 within each imaging station 15 is initiallycharged by a primary charging station 2. This charge is then modified bya printhead 3 (e.g., LED printhead) to create an electrostatic image onthe primary image member 1. A development station 4 deposits markingparticles on the primary image member 1 to form a marking particle imagecorresponding to the color toner in each individual imaging station 15.The marking particle image is electrostatically transferred from theprimary image member 1 to an intermediate transfer member, for example,an intermediate transfer roller or drum 5. While both of the primaryimage member 1 and the intermediate transfer drum 5 are shown as drums,as would be known by one of ordinary skill in the art, these could alsoinclude belts or similar image transfer surfaces. The primary imagemember 1 and the intermediate transfer drum 5 are used in these examplesto simplify the explanation of the invention; however, the invention isnot limited to drums, but instead, is applicable to all similarstructures/surfaces.

After the charged marking particles are transferred to the intermediatetransfer drum 5, there still remains some waste marking particles thatneed to be removed from the primary image member 1. The invention uses apre-cleaning erase light emitting diode (LED) lamp 9 in combination witha pre-cleaning charging station 10 in order to electrostatically modifythe surface potential of the non-image areas of the primary image member1 and the charge on the waste marking particles remaining on the primaryimage member 1, respectively. In addition, a cleaning station 8 isincluded to physically remove any remaining waste marking particles. Thecleaning station 8 is illustrated in FIG. 2 and is discussed in greaterdetail below.

A transfer nip is used between a transfer backer roller 7 and theintermediate transfer drum 5 to transfer the marking particle image to areceiving sheet 25. In a similar manner to that discussed above, theremaining waste marking particles that remain on the intermediatetransfer drum 5 after the marking particle image has been transferred tothe receiving sheet 25 are removed using a pre-cleaning charging station12 and a cleaning station 11. Once again, the details of the cleaningstation 11 are shown in FIG. 2 and are discussed below in detail. Thereceiving sheet 25 is transported by the dielectric conveyor 6 to afuser 30 where the marking particle image is fixed by conventionalmeans. The receiving sheet 25 is then conveyed from the fuser 30 to anoutput tray 35.

The marking particle image is transferred from the primary image member1 to the intermediate transfer drum 5 in response to an electric fieldapplied between the core of intermediate transfer drum 5 and aconductive electrode forming a part of the primary image member 1. Themarking particle image is transferred to the receiving sheet 25 at thenip in response to an electric field created between the transfer backerroller 7 and the intermediate transfer drum 5. Thus, intermediatetransfer drum 5 helps establish both electric fields. As is known in theart, a polyurethane roller containing an appropriate amount ofanti-static material to make it of at least intermediate electricalconductivity can be used for establishing both fields. Typically, thepolyurethane or other elastomer is a relatively thick layer; e.g.,one-quarter inch thick, which has been formed on an aluminum base.

Preferably, the electrode buried in the primary image member 1 isgrounded for convenience in cooperating with the other stations informing the electrostatic and toner images. If the marking particles area positively-charged toner, an electrical bias V_(ITM) applied tointermediate transfer drum 5 of typically −300 to −1,500 volts willeffect substantial transfer of marking particle images to theintermediate transfer drum. To then transfer the marking particle imageonto a receiving sheet 25, a bias, e.g., of −2,000 volts or greaternegative voltages, is applied to transfer backer roller 7 to again urgethe positively-charged marking particles to transfer to the receivingsheet 25. Schemes are also known in the art for changing the bias onintermediate transfer drum 5 between the two transfer locations so thattransfer backer roller 7 need not be at such a high potential.

The intermediate transfer drum 5 has a polyurethane base layer uponwhich a thin skin is coated or otherwise formed having the desiredrelease characteristics. The polyurethane base layer preferably issupported upon an aluminum core. The thin skin may be a thermoplasticand should be relatively hard, preferably having a Young's modulus inexcess of 5×10⁷ Newtons per square meter to facilitate release of themarking particles to ordinary paper or another type of receiving sheet25. The base layer is preferably compliant and has a Young's modulus of10⁷ Newtons per square meter or less to assure good compliance for eachtransfer.

With reference also now to FIG. 2, the cleaning station 11 comprises ahousing 32 which encloses a cleaning brush 34 having conductive fibers(fur) 36 which, through an opening in the housing 32, engage theintermediate transfer drum 5.

The cleaning brush 34 is supported on a core 35 which is driven torotate by a motor M or other motive source to rotate in the direction ofarrow A as the intermediate transfer drum 5 is moved in the directionshown by arrow B. As the cleaning brush 34 rotates, untransferredmarking particles 60 and other particulate debris, such as carrierparticles and paper dust on the intermediate transfer drum 5, aremechanically scrubbed from the intermediate transfer drum 5 and pickedup into the fibers 36 of the cleaning brush 34. The items illustrated inthe figures are generally not shown to scale to facilitate understandingof the structure and operation of the apparatus. In particular, thefibers 36 are shown much larger to scale than other structures shown inFIG. 2.

In addition to mechanical scrubbing, an electrical bias is applied tothe cleaning brush 34 from power supply 39. An electrical bias V1 of thepower supply 39 to the cleaning brush 34 is, as will be more fullyexplained below, inductively, and not conductively, coupled to theconductive fibers or brush fibers 36. A voltage V1 is greater than thevoltage bias V_(ITM) applied to the intermediate transfer drum 5. Thepolarity of the voltage on the brush fibers 36 is such as toelectrostatically attract marking particles 60 to the brush fibers 36.The marking particles 60 entrained within the brush fibers 36 arecarried to a rotating detoning roller 40 which is electrically biased bypower supply 39 to a higher voltage level V2 than the voltage level V1;i.e., the voltage level V2 is of a level to electrostatically attractthe marking particles 60 in the cleaning brush 34 to the detoning roller40. Assuming a positively-charged marking particle image, as an example,the marking particle image may be attracted to the intermediate transferdrum 5 which is biased to the voltage bias V_(ITM) in the range of about−300 volts to about −1500 volts. The cleaning brush 34, in such anexample, would be biased to a potential V1 which is in the range ofabout −550 volts to about −1750 volts. The detoning roller 40 in thisexample would be biased to a potential V2 which is in the range of about−800 volts to about −2000 volts. In considering relationships of voltageV2>V1>V_(ITM), the absolute values of the voltages are implied.

The marking particles 60 are electrostatically attracted to the surface41 of the detoning roller 40. The surface of detoning roller 40 isrotated in the direction of arrow C by a drive force from motor Mcounter to that of the brush fibers 36 or alternatively in the samedirection. The marking particles 60 are carried by the surface 41 of thedetoning roller 40 toward a stationary skive blade 42 which is supportedas a cantilever at end 42 a so that the scraping end 42 b of the skiveblade 42 engages the surface 41 of the detoning roller 40.

Marking particles 60 scrubbed from the surface 41 are allowed to fallinto a collection chamber 51 of housing 32 and periodically a driveforce, such as from motor M or another motive source, is provided tocause an auger 50 or other marking particle transport device to feed themarking particles 60 to a waste receptacle. Alternatively, the wastereceptacle may be provided, attached to housing 32, so that markingparticles 60 fall into the waste receptacle directly and the auger 50may be eliminated. In order to ensure intimate contact between thedetoning roller surface 41 and the skive blade 42, a permanent magnet isstationarily supported within the hollow enclosure of the detoningroller 40.

The skive blade 42 is made of a metal such as ferromagnetic steel and isof a thickness of less than 0.5 mm and is magnetically attracted by themagnet to the detoning roller surface 41. This effectively minimizes thetendency of the scraping end 42 b to chatter as the surface 41 travelspast the scraping end 42 b and thus provides more reliable skiving ofthe marking particles 60 and, therefore, provides improved imagereproduction. The skive blade 42 extends for the full working width ofthe detoning roller surface 41 and is supported at its end 42 a by ears42 c which are soldered to the skive blade 42. A pin extends through ahole in the ears 42 c to connect the skive blade 42 to the housing 32.

The detoning roller 40 preferably comprises a marking or developmentroller as is used in known SPD-type development stations which include acore of permanent magnets surrounded by a metal sleeve 41 a. As adetoning roller 40, the magnetic core is formed of a series ofalternately arranged poles (north-south-north-south), permanent magnetsthat are stationary when in operation. Sleeve 41 a is formed of polishedaluminum or stainless steel and is electrically conductive, butnonmagnetic, so as to not reduce the magnetic attraction of the skiveblade 42 to the magnets in the core. The sleeve 41 a is driven inrotation in the direction of arrow C and is electrically connected topotential V2.

FIG. 3 illustrates the cleaning assembly 11 shown in FIG. 2 in greaterdetail. As discussed above, marking particles 60 are removed from thedetoning roller 40 by the skive blade 42 become airborne and can beattracted back to the cleaning brush 34. This reduces the efficiency ofthe cleaning assembly 11 because marking particles 60 may have to beremoved from the cleaning brush 34 a number of times before they reach awaste chamber. More importantly, it is also possible for such airbornewaste marking particles 60 to be carried outside the cleaning assembly11 through the viscous boundary layer of air created by the rotation ofthe cleaning brush 34. If this waste marking particles exit the cleaningassembly 11, it can contaminate the remaining portions of the imageprocessing apparatus. The inventive cleaning assembly 11 shown in FIG. 3prevents waste marking particles 60 that are removed from the detoningroller 40 from becoming airborne and re-entering the scavenging zone ofthe cleaning assembly 11. More specifically, the invention addressesthis problem by providing a solution that uses flaps 300-302 to dividethe cleaning assembly 11 into a scavenging zone and a detoning zone (asconceptually illustrated by the dashed line crossing FIG. 3) whereby,once the waste marking particles 60 enter the detoning zone, they areprevented from re-entering the scavenging zone.

FIG. 3 illustrates an upper skive flap 300 that is connected between thetop of the skive blade 42 and the housing or outer casing 32.Additionally, the skive 42 includes a lower skive flap 301 that isrigidly attached to the skive blade 42 and is biased against thedetoning roller 40. More specifically, the lower skive flap 301 hassufficient rigidity that it is held against the detoning roller 40. Inaddition, a bottom flap 302 is connected to the lower part of the outercasing 32 and is biased against the detoning roller 40. Each of theflaps 300-302 includes additional material at the ends of the flaps300-302 which is curved and extends into the detoning zone. Thisadditional material insures that the flaps 300-302 will continue to makecontact with the movable elements (detoning roller 40, skive blade 42)even if there are large size and position variations of the outer casing32, skive blade 42, detoning roller 40 caused by manufacturingvariations. These flaps can be constructed out of a non-conductivepolymeric material such as Mylar® (DuPont High Performance Materials,P.O. Box 89, Route 23 South and DuPont Road, Circleville, Ohio 43113),plush fabric, air curtains anywhere from “0.001 to 0.003” thick andattached to the outer casing 32 of the cleaner or skive blade 42 with anadhesive backing on the flap 300-302. The flap 302 needs to be ofsufficient flexibility to allow waste marking particles 60 to pass intothe detoning zone from the scavenging zone.

While the invention illustrates three flaps 300-302, the invention isnot limited to the specific structure shown in FIG. 3. To the contrary,the invention could include more or fewer flaps, depending upon thespecific shape of the various components within the cleaning assembly11. Also, the invention is not limited to the use of flaps 300-302, butcould also make use of fabric plush material to effect the propersealing between the scavenging and detoning zones. Indeed, the inventionis applicable to all such cleaning assemblies that need to controlairborne marking particles. Thus, the invention is not limited to thespecific embodiments described herein, but is applicable to allstructures that utilize flaps or plushes within the cleaning assembly 11to control airborne marking particles.

The invention physically separates the cleaning assembly 11 into ascavenging zone and a detoning zone using, for example, flaps 300-302 orplushes. Such physically separated zones reduce the volume of markingparticles 60 from the scavenging zone to increase the cleaningefficiency of the operating components in the scavenging zone. Byproviding physical structures that create zones, the invention issuperior to conventional structures and contains marking particleswithin the detoning zone, thereby reducing marking particlecontamination of the cleaning (detoning) components of the cleaningassembly.

While the invention has been described in terms of preferredembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theappended claims.

PARTS LIST Item Description 1 primary image member 2 primary chargingstation 3 printhead 4 development station 5 intermediate transfer drum 6conveyor 7 transfer backer roller 8 cleaning station 9 pre-cleaningerase LED lamp 10 pre-cleaning charging station 11 cleaning assembly 12pre-cleaning charging station 15 imaging station 25 receiving sheet 30fuser 32 casing/housing 34 cleaning brush 35 output tray 36 fibers 39power supply 40 detoning roller 41 surface 41a sleeve 42 skive blade 42ablade end 42b scraping blade end 42c blade ears 50 auger 51 collectionchamber 60 marking particles 300 upper skive flap 301 lower skive flap302 bottom skive flap

What is claimed is:
 1. A conductive fur brush cleaning assembly for animage processing apparatus, said cleaning assembly comprising: a casing;a plurality of rotating components within said casing; and a pluralityof sealing devices that divide said casing into a scavenging zone and adetoning zone, at least one of said plurality of sealing devices is aplush fabric seal; wherein said plurality of sealing devices preventairborne marking particles from traveling from said detoning zone intosaid scavenging zone.
 2. The cleaning assembly in claim 1, wherein saidplurality of rotating components include a detoning roller and at leastone of said plurality of sealing devices contacts said detoning roller.3. The cleaning assembly in claim 1, wherein at least one of saidplurality of sealing devices comprises a flap.
 4. The cleaning assemblyin claim 1, wherein said plurality of sealing devices additionallyemploy another from the list of: air curtains, flaps, and plush fabricseals.
 5. A conductive fur brush cleaning assembly for an imageprocessing apparatus, said cleaning assembly comprising: a casing; aplurality of rotating components within said casing; and a plurality ofsealing flaps connected to said casing that divide said casing into ascavenging zone and a detoning zone, said plurality of sealing flaps area non-conductive polymeric material; wherein said plurality of sealingflaps prevent airborne marking particles from traveling from saiddetoning zone into said scavenging zone.
 6. The cleaning assembly inclaim 5, wherein said plurality of rotating components include adetoning roller and at least one of said plurality of sealing flapscontacts said detoning roller.
 7. The cleaning assembly in claim 5,wherein at least one of said plurality of sealing flaps includes a plushfabric seal.
 8. The cleaning assembly in claim 5, wherein said pluralityof sealing flaps include a curved end portion that extends into saiddetoning zone, wherein said curved end portion to rebounds said airbornemarking particles toward said detoning zone.
 9. The cleaning assembly inclaim 5, wherein said plurality of rotating components include adetoning roller, and said plurality of sealing flaps include a bottomflap attached to a lower portion of said casing, by contact with saiddetoning roller.
 10. The cleaning assembly in claim 9, furthercomprising a skive blade attached to said casing, wherein said skiveblade contacts said detoning roller to remove marking particles fromsaid detoning roller, wherein said plurality of sealing flaps include anupper skive flap connected to an upper portion of said casing and to anupper portion of said skive blade.
 11. The cleaning assembly in claim10, wherein said plurality of sealing flaps include a lower skive flapconnected to a lower portion of said skive blade, and wherein said lowerskive flap is in contact with said detoning roller.